Sterile container

ABSTRACT

A sterile container is provided, especially for receiving and containing surgical instruments or material in sterile conditions, comprising a receiving area formed by a container bottom and container walls, a lid for sealing the receiving are, and a gas exchange opening which can be sealed by a sterile filter maintained in a filter holder. In order to simplify replacement of the sterile filter and to simplify the production of the lid, the sterile filter and filter holder form a filter unit and the filter holder is mounted on the lid.

This application is a continuation of, commonly assigned U.S. patentapplication Ser. No. 10/846,485 filed on May 13, 2004 now U.S. Pat. No.6,994,128 which is a continuation of International patent applicationno. PCT/EP02/12671 filed on Nov. 13, 2002, and which claims the benefitof German patent application no. 101 56 937.8 filed on Nov. 15, 2001 andGerman patent application no. 102 10 905.2 filed on Mar. 6, 2002, eachof which is incorporated herein and made a part hereof by reference.

BACKGROUND OF THE INVENTION

The invention relates to a sterile container, in particular for theholding and sterile storage of surgical instruments or material,comprising a holding space, which is defined by a container base andcontainer walls, a lid for closing the holding space and a gas exchangeopening, which can be closed off by a sterile filter held in a filterholder.

Sterile containers of this type, together with, for example, surgicalinstruments or material stored therein, are sterilized in a sterilizer.They can then be transferred to a sterile operating region, where theycan be opened. The sterile filter is required in order to prevent germsfrom penetrating into the holding space of the container following thesterilization operation. However, this filter has to be replaced fromtime to time. In known sterile containers, this can be achieved onlywith difficulty. Moreover, production of a lid with filter holderarranged integrally thereon is very complex.

Therefore, it is an object of the present invention to improve a sterilecontainer of the type described in the introduction in such a way thatthe sterile filter can easily be exchanged and the lid is particularlysimple to produce.

SUMMARY OF THE INVENTION

In a sterile container of the type described in the introduction, thisobject is achieved, according to the invention, by virtue of the factthat the sterile filter and the filter holder form a filter unit, andthat the filter holder is mounted on the lid.

This configuration allows the filter unit to be exchanged in full ifnecessary. For this purpose, in particular during insertion, there is nolonger any need to take hold of the sterile filter itself, with theresult that firstly damage to the filter is avoided, and secondlysoiling is prevented. Production of the lid is additionally simplified,since the filter holder can be retrofitted to the lid.

It is advantageous if the sterile filter and the filter holder can bereleasably connected, if the sterile filter can be released from thefilter holder in a removal position and is held on the filter holder ina connection position. This means that when the filter is beingexchanged, only the sterile filter has to be renewed, rather than theentire filter unit. Although the entire filter unit could be exchanged,if the filter holder were still intact it would have been replacedunnecessarily. The overall economic viability of the sterile containeris improved as a result.

To prevent damage to the sterile filter, it is advantageous if thesterile filter is held on a carrier element.

To increase the stability and retain the shape of the sterile filter, itis expedient if the carrier element comprises a first and a secondsupport element, and if the sterile filter is held between the twosupport elements. This allows the sterile filter to be gripped reliablyby the carrier element without soiling or damaging the filter.

To further increase the stability of the filter unit, it is possible toprovide that at least one of the two support elements comprisessupporting sections, which span at least partially the gas exchangeopening, for supporting the sterile filter. Although this reduces thesize of the gas exchange opening, it also reduces the size of freesurfaces of the sterile filter, so that its shape can be stabilized,which is advantageous in particular when pressurized hot steam isapplied.

According to a preferred embodiment of the invention, it is possible toprovide that the sterile filter, the first and second support elementsare nonreleasably connected to one another, in particular by adhesivebonding, clamping or welding. The overall result is a dimensionallystable unit comprising the carrier element and the sterile filter,making it easier to exchange the latter.

The carrier element and the filter holder can be connected to oneanother in various ways, for example by screw connection or clamping.However, it is particularly advantageous if there is provided a bayonetconnection for connecting the carrier element and the filter holder andfor transferring the carrier element from the removal position into theconnection position. The carrier element can easily be connected to thesterile filter, specifically by the carrier element firstly beinginserted into the filter holder and then rotated through a definedangular range, which substantially depends on the number of bayonetprojections and recesses which can be brought into engagement with oneanother and the angular extent thereof. The connection position isusually defined by relative stops between the carrier element and thefilter holder, which delimit a rotary movement.

To ensure a defined connection position and to prevent the sterilefilter from being released from the filter holder, it is expedient ifthere is provided a locking mechanism for locking the connectionposition of the sterile filter and the filter holder.

A locking mechanism can be realized in particularly simple form by alatching connection.

In a further advantageous embodiment of the invention, it is possible toprovide that the filter unit comprises a cover for covering the sterilefilter on one side. This provides the sterile filter with protectionagainst damage, for example from objects stored in the sterilecontainer, on one side.

To ensure optimum gas exchange and, at the same time, to reliablyprotect the sterile filter from damage, it may be advantageous if thecover is provided with apertures for allowing gas exchange through theapertures, and if the apertures are covered by aperture covers in adirection which is transverse with respect to a flow-permittingdirection.

It is preferable for the cover to be spaced apart from the sterilefilter. This prevents the sterile filter from coming into contact withthe cover in the event of exposure to hot steam should the sterilefilter be deformed, for example bulge out.

Although the cover and the filter holder could be formed integrally, ina preferred embodiment of the invention, however, it is possible toprovide that the cover can be releasably connected to the filter holder,that the cover can be detached from the filter holder in a detachmentposition and is held on the filter holder in a closure position. Thisallows simple removal of the cover in order to exchange the sterilefilter.

The cover could, for example, be secured to the filter holder usingscrews or clips, but it is particularly advantageous if there isprovided a second bayonet connection for connecting the cover and thefilter holder and for transferring the cover from the detachmentposition into the closure position. A connection could, for example, beproduced by introducing corresponding projections of the cover intorecesses in the filter holder and then rotating the cover as a wholerelative to the filter holder. The cover can easily be removed byreversing this operation.

To prevent the cover from unintentionally becoming detached from thefilter holder, there is provided a second locking mechanism for lockingthe cover and the filter holder in the closure position.

The second locking mechanism could, for example, be realized by means ofa separately actuable locking element. However, it is particularlysimple if the second locking mechanism comprises a second latchingconnection. This allows all types of latching connections, for exampleresiliently mounted latching projections, which engage in correspondingrecesses.

Furthermore, it is advantageous if the carrier element comprises acentering element, which can be brought into engagement with the cover,in order to center the cover on the filter holder. This in particularfacilitates and simplifies fitting of the cover. Moreover, the centeringaid can also serve as a stop in order to help to avoid damage to thesterile filter by the cover.

To additionally control and/or regulate gas exchange between the holdingspace and the vicinity of the sterile container, it may be expedient ifthe filter unit is mounted moveably, if the filter unit, in a closedposition, closes a flow path and, in a flow-permitting position, opensthe flow path, so that gas exchange in the closed position is possibleonly through the sterile filter and in the flow-permitting position ispossible through the sterile filter and/or through the flow path. Thisallows the filter unit, in particular if greater gas exchange isrequired, to be transferred into the flow-permitting position so that anadditional flow path is opened up.

Assembly of the sterile container becomes particularly simple ifmounting elements are provided on the filter holder and on the lid formounting the filter unit on the lid.

A particularly simple structure of the sterile container with a moveablymounted filter unit advantageously results if the mounting elementscomprise at least one mounting bolt and an associated mounting bush, ifthe mounting bolt at each end has a stop for limiting a movement of themounting bush relative to the mounting bolt, and if the mounting bolt isdisposed on the lid and the mounting bush is disposed on the filterholder, or vice versa.

No additional parts are required if one of the two stops is formed bythe lid and the other stop is formed by a head of the mounting bolt.

Additional protection for the mounting elements is obtained if the covercovers the mounting elements. In this way, the mounting elements areprotected from unintentional manipulation.

To close an additional flow path and thereby to allow objects stored inthe sterile container to be kept free of germs, the filter unit is heldon the sterile container under preload in the closed position.

A preload of this type can be realized particularly easily if an elementwhich has a preloading action in the longitudinal direction of themounting bolt is supported between one of the two stops and the mountingbush. Any desired elastic elements, for example coil springs orelastomeric elements, can be used as preloading element.

It is advantageous if there is provided a sealing element for mountingthe filter unit on the lid in a gastight manner. This allows completesealing of the filter unit on the lid, so that gas exchange is possibleonly through the sterile filter.

It is particularly expedient if the sealing element comprises a sealingring mounted on the carrier element. Sealing rings are particularlysimple to produce and can be disposed on the carrier element in a simpleway.

According to a further preferred embodiment of the invention, it isadvantageous if there is provided a pressure-relief valve, if thepressure-relief valve is disposed in such a way that in a basic positionit adopts a closed position, and if it adopts a flow-permitting positionwhen a pressure in the vicinity of the sterile container exceeds apressure in the sterile container by a predetermined pressuredifference. In this way, it is possible to avoid damage to the sterilecontainer, since the pressure-relief valve opens, allowing gas to flowinto the container, before the sterile container can be deformed as aresult of a particularly high pressure in the surrounding region or acorrespondingly high pressure gradient.

No additional components or further apertures are required if the filterunit forms the pressure-relief valve. The filter unit therefore performstwo functions; firstly it serves to block germs, and secondly it servesas a pressure-relief valve.

There is preferably provided a protective element which covers thefilter unit at a spacing therefrom. This in particular makes it possibleto reliably protect the sterile filter against mechanical damage.

It is particularly expedient if the filter unit is mounted on an innerside of the lid and if the protective element is disposed on an outerside of the lid. This means that the filter unit comprising the sterilefilter is reliably protected against mechanical damage from both sides.

To minimize the amount of liquid which reaches the sterile filter, it isadvantageous if between the protective element and the lid there isprovided at least one opening for the passage of gas, which is in fluidcommunication with the gas exchange opening and is disposed in such away that gas flow is possible in a direction of flow runningsubstantially transversely with respect to the flow-permitting directionof the sterile filter. In this way, gas, for example hot steam forsterilization, can easily pass through the sterile filter, whereasliquids are initially kept away from the sterile filter.

To make it even more difficult for liquids to penetrate into the filterunit, it is expedient if there is provided an inflow edge which isdisposed on the outer side of the lid, faces away from the gas exchangeopening and slopes downward toward the outside relative to a lid plane.If liquid reaches the lid, the inclination of the inflow edge away fromthe gas exchange opening means that it can flow away and thereforecannot reach the filter unit.

To facilitate installation of the filter holder and to increase thestability of the latter, in a preferred embodiment of the invention itis provided that the filter holder is mounted on the lid in a mannerwhich is secured against rotation.

It is preferable for the sterile filter to be a long-term filter, inparticular made from polytetrafluoroethylene (PTFE). This makes itpossible to extend the intervals between maintenance of the sterilecontainer, meaning that the filter unit only seldom has to be exchanged.

The sterile container becomes particularly efficient and simple toproduce if the lid is made from a plastic, in particular from polyetherether ketone (PEEK) or polyphenylene sulfone (PPSU).

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of a preferred embodiment of the invention, inconjunction with the drawing, serves to provide a more detailedexplanation. In the drawing:

FIG. 1: shows an exploded view of a dismantled, three-part filter unit;

FIG. 2: shows a sectional view on line 2-2 in FIG. 1, and

FIG. 3: shows a sectional view on line 3-3 in FIG. 1.

DETAILED DESCRIPTION

FIGS. 1 to 3 illustrate a three-part filter unit, which is denotedoverall by reference numeral 10 and is mounted on a lid 12 of a sterilecontainer (not shown in more detail).

The filter unit 10 comprises a holding frame 14, which can be connectedto the lid 12, a filter element 16, which can be placed into the holdingframe 14 and connected to the latter, and a cover 18 which can beconnected to the holding frame 14.

The holding frame 14 comprises a cover plate 20 which has an octagonalexternal contour and also has a circular opening 22 surrounded by anencircling inner rim 24. An encircling outer rim 26 adjoins theoctagonal outer contour of the cover plate 20, so that a hollow profilewhich is substantially U-shaped in cross section is formed. Fouridentical cylindrical sleeves, serving as mounting bushes 28, areinserted into the cover plate, in each case offset by 90° in thecircumferential direction, which sleeves, at their end remote from thecover plate 20, have an annular flange 30 facing inward and runningparallel to the cover plate 20. Between the mounting bushes 28 aredisposed four identical slots 32, which extend over an angular range ofapproximately 45° and are partially covered by a projection 34, which isformed integrally with the cover plate 20 and is adjoined by anintegrally formed, resilient latching lug 36 which faces in thecircumferential direction, which can be moved to a slight extentperpendicular to the cover plate 20 and, on a side facing away from thecover plate 20, has a small spherical projection (not shown). Theprojection 34 and the latching lug 36 cover approximately 40% of theslot 32 in the circumferential direction starting from one end of theslot 32.

Furthermore, the inner rim 24 is provided with four radial projections38, which are distributed symmetrically over the circumference, extendin the circumferential direction, project radially inward and extendover an angular range of approximately 40°. On one side, the radialprojections 38 are extended by latching tongues 40 which protrude in aparallel offset manner and can be moved to a slight extent perpendicularto the cover plate 20.

A free rim contour 27, facing away from the cover plate 20, of the outerrim 26 is partially curved and configured so as to correspond to aninner surface (not shown in more detail) of the lid 12, so that it ispossible to realize positively locking placement of the holding frame 14against the lid 12.

The filter element 16 comprises two clamping disks 42 and 43, which havean inner ring 45 and 49, respectively, in each case connected via eightradially extending webs 46 and 50, respectively, to an outer ring 44 and48, respectively. Four holding webs 54, which are disposed in a crossshape and centrally carry a centering projection 56, pass through theinner ring 45 of the clamping disk 42. Between the clamping disks 42 and43 there is a sterile filter 52 which completely covers the annularopening 58 delimited by the outer rings 44 and 48. The two clampingdisks 42 and 43 and the sterile filter 52 are fixedly connected to oneanother, for example by adhesive bonding or ultrasound welding, and forma single unit.

The external diameter of the annular filter element 16 corresponds tothe internal diameter of the opening 22 of the holding frame 14 and cantherefore be inserted into this opening 22. To connect the filterelement 16 to the holding frame 14, the outer ring 48 is provided withfour receiving grooves 60, which are distributed symmetrically over thecircumference and are open to the radially outer side. In each case onelateral end of the receiving groove 60 is closed off by a groove endwall 62. The filter element 16 is inserted into the holding frame 14 insuch a manner that the four receiving grooves 60 engage between thoseregions of the inner rim 24 which are provided with the radialprojections 38. A radially protruding outer annular flange 64 of theouter ring 48 in this position is supported on the radial projections38. The filter element 16 is then rotated until the groove end wall 62comes to a stop against the end edge 39 of the radial projection 38engaging in the receiving groove 60. In this connection position of theholding frame 14 and the filter element 16, the projections disposed onthe latching tongue 40 penetrate into corresponding recesses 66 at theopen end of in each case one side wall 61 of the receiving groove,resulting in latching locking of the connection position.

Furthermore, the outer ring 48 is provided with an annular groove 68which is open in the direction facing away from the outer ring 44 andinto which a sealing ring 70 is inserted.

The filter unit 10 is closed off by means of the cover 18, which has anoctagonal baseplate 72 which corresponds to the outer contour of thecover plate 20 and is provided with a central bore 74 for introductionof the centering projection 56. A circular surface region 76 is providedwith slots 78 of different lengths in each case running parallel inquarter-circle sectors, so that webs 80 remain between the slots 78,protruding as extensions running obliquely, approximately at an angle of60°, relative to the baseplate 72. Obliquely running web regions formaperture covers 81 that in each case completely cover the slots 78, sothat obliquely extending passages 82 are formed in each case. Directpassage through the slots 78 perpendicular to the baseplate 72 is notpossible.

Four symmetrically distributed retaining projections 86, which areL-shaped in cross section, extend over an angular range of approximately30° and one free limb of which, at one of its ends, has a bore 88running perpendicular to the baseplate 72, project from an underside 84of the baseplate 72.

The cover 18 is connected to the holding frame 14 in the following way:the cover 18 is introduced, by means of the retaining projections 86,into regions of the slots 32 which are not covered by projections 34,until the underside 84 of the baseplate 72 bears against the cover plate20. Rotation of the cover 18 in the clockwise direction causes the freelimbs of the retaining projections 86 to engage behind the projections34 until an end side 87 of the retaining projection 86 comes to a stopat an end edge 33 of the slot 32. In this closure position, a hemisphere37 disposed on the latching lug 36 penetrates into the bore 88 and locksthe closure position of the cover 18 and of the holding frame 14.

The securing of the holding frame 14 to the lid 12 is explained inconjunction with FIG. 2. On the lid 12, adjacent to a circular aperture(not shown), on its inner side there are disposed four substantiallycylindrical holding bolts 90 protruding perpendicularly away from thelid 12. The mounting bushes 28 of the holding frame 14 are pushed overthe holding bolts 90, so that the annular flanges 30 engage against theinner side of the lid 12, surrounding the holding bolts 90. Each holdingbolt 90 is surrounded by a coil spring 92, which on one side issupported against the annular flange 30 and on the other side issupported against an annular flange 94 of a cover 96 which has a centralbore 97, the internal diameter of which corresponds to the externaldiameter of the holding bolt 90. The cover 96 is ultrasonically weldedor adhesively bonded to the holding bolt.

This mounting arrangement makes it possible for the entire filter unit10 to be lifted off the inner side of the lid 12 counter to theprestress of the coil springs 92. This occurs, for example, if a sterilecontainer with a filter unit 10 disposed thereon is introduced into asterilizer and acted on by pressurized hot steam. The pressuresurrounding the sterile container is in this case higher than thepressure in the interior of the container, so that the entire filterunit 10 lifts off the lid 12 and opens up an additional flow path forhot steam to flow in. This prevents the sterile container from beingdeformed by the action of excessive pressure differences. If theexternally acting pressure drops again, the filter unit 10 is preloadedonto the inner side of the lid 12 by means of the coil springs 92. Thesealing ring 70, in this closed position, engages against acorresponding sealing projection 98 of the lid 12, so that gas exchangeis then only possible through the sterile filter 52 into the interior ofthe sterile container. On account of this resilient mounting, the entirefilter unit 10 simultaneously also performs the function of apressure-relief valve.

1. Sterile container, in particular for the holding and sterile storageof surgical instruments or material, comprising: a holding space definedby a container base and container walls, a lid for closing the holdingspace, a filter holder movably mounted on said lid, a sterile filterheld in said filter holder, the sterile filter and the filter holderforming a filter unit, and a gas exchange opening being closeable bysaid sterile filter; wherein the filter holder is movable verticallywith respect to the lid when mounted on the lid in a manner which issecured against rotation.
 2. Sterile container according to claim 1,wherein the sterile filter and the filter holder can be releasablyconnected, in that the sterile filter can be released from the filterholder in a removal position and is held on the filter holder in aconnection position.
 3. Sterile container according to claim 2, whereinthere is provided a locking mechanism for locking the connectionposition of the sterile filter and the filter holder.
 4. Sterilecontainer according to claim 3, wherein the locking mechanism comprisesa latching connection.
 5. Sterile container according to claim 1,wherein the sterile filter is held on a carrier element.
 6. Sterilecontainer according to claim 5, wherein there is provided a bayonetconnection for connecting the carrier element and the filter holder andfor transferring the carrier element from the removal position into theconnection position.
 7. Sterile container according to claim 5, whereinthe carrier element comprises a first and a second support element, andwherein the sterile filter is held between the two support elements. 8.Sterile container according to claim 7, wherein at least one of the twosupport elements comprises supporting sections, which span at leastpartially the gas exchange opening, for supporting the sterile filter.9. Sterile container according to claim 7, wherein the sterile filter,the first and second support elements are nonreleasably connected to oneanother, in particular by adhesive bonding, clamping or welding. 10.Sterile container according to claim 1, wherein the filter unitcomprises a cover for covering the sterile filter on one side. 11.Sterile container according claim 10, wherein the cover is provided withapertures for allowing gas exchange through the apertures, and whereinthe apertures are covered by aperture covers in a direction which istransverse with respect to a flow-permitting direction.
 12. Sterilecontainer according to claim 10, wherein the cover is spaced apart fromthe sterile filter.
 13. Sterile container according to claim 10, whereinthe cover can be releasably connected to the filter holder, and whereinthe cover can be detached from the filter holder in a detachmentposition and is held on the filter holder in a closure position. 14.Sterile container according to claim 13, wherein there is provided asecond bayonet connection for connecting the cover and the filter holderand for transferring the cover from the detachment position into theclosure position.
 15. Sterile container according to claim 13 whereinthere is provided a second locking mechanism for locking the cover andthe filter holder in the closure position.
 16. Sterile containeraccording to claim 15, wherein the second locking mechanism comprises asecond latching connection.
 17. Sterile container according to claim 10,wherein the carrier element comprises a centering element, which can bebrought into engagement with the cover, in order to center the cover onthe filter holder.
 18. Sterile container according to claim 1, whereinmounting elements are provided on the filter holder and on the lid formounting the filter unit on the lid.
 19. Sterile container according toclaim 1, wherein the filter unit is held on the sterile container underpreload in the closed position.
 20. Sterile container according to claim1, wherein there is provided a sealing element for mounting the filterunit on the lid in a gastight manner.
 21. Sterile container according toclaim 20, wherein the sealing element comprises a sealing ring mountedon the carrier element.
 22. Sterile container according to claim 1,wherein there is provided a protective element which covers the filterunit at a spacing therefrom.
 23. Sterile container according to claim 1,wherein the sterile filter is a long-term filter, in particular madefrom polytetrafluoroethylene (PTFE).
 24. Sterile container according toclaim 1, wherein the lid (12) is made from a plastic, in particular frompolyether ether ketone (PEEK) or polyphenylene sulfone (PPSU). 25.Sterile container according to claim 1, wherein the movably mountedfilter holder is adapted to function as a pressure relief valve. 26.Sterile container comprising: a holding space defined by a containerbase and container walls, a lid for closing the holding space, a filterholder movably mounted on said lid, a sterile filter held in said filterholder, the sterile filter and the filter holder forming a filter unit,a gas exchange opening being closeable by said sterile filter; andmounting elements provided on the filter holder and on the lid formovably mounting the filter holder on the lid; wherein the mountingelements comprise at least one mounting bolt and an associated mountingbush, wherein the mounting bolt at each end has a stop for limiting amovement of the mounting bush relative to the mounting bolt, and whereinthe mounting bolt is disposed on the lid and the mounting bush isdisposed on the filter holder, or vice versa.
 27. Sterile containeraccording to claim 26, wherein an element which has a preloading actionin the longitudinal direction of the mounting bolt is supported betweenone of the two stops and the mounting bush.
 28. Device according toclaim 26, wherein the filter holder is mounted on the lid in a mannerwhich is secured against rotation.